This invention relates generally to graphical user interfaces and in particular to a touchscreen display system used in conjunction with associated indicators for controlling a handheld, electronic test instrument.
Electronic test instruments such as oscilloscopes have traditionally used graphical display in conjunction with softkeys to obtain an improved user interface. In the typical user interface, softkeys are placed around the periphery of the graphical display, either in the form of a cathode ray tube (CRT) or, more recently, liquid crystal displays (LCDs). Softkey labels are drawn on the graphical display adjacent to the softkey, so that the function and action associated with the softkey may be readily defined and re-defined according to the particular state of the user interface.
Touchscreen technology has provided a more recent innovation in user interface technology by allowing the user to touch a designated area of the graphical interface to generate an output signal rather than pressing a softkey adjacent to the graphical interface. Graphical displays employing colors are now available to further enhance instrument usability. Touchscreen display technology has largely been driven by the market demands of the computer industry for the personal digital assistant (PDA) which is designed as a portable, hand-held computer. By combining the functions of user input and graphical display output, the touchscreen user interface can be implemented in a smaller physical space, with enhanced versatility and reduced cost.
Handheld, portable test instruments have been developed that successfully employ graphical user interfaces in combination with softkeys, including portable digital storage oscilloscopes (DSOs) and local area network (LAN) test instruments. Most portable test instruments have substantial constraints on size and battery power which dictates the use of LCD technology for graphical user interfaces.
Portable test instruments with LCD graphical displays are increasingly being used in service, installation, and maintenance applications which often involve cramped locations and poor lighting conditions, by technicians who may only need to see certain basic information about what is being measured. LCD display technology, while extensively used in touchscreen user interfaces, often requires power consuming backlight circuits in order generate light in order to be seen in low ambient light conditions. The information on LCD displays is visible only from limited viewing angles which makes the operation of the portable test instrument more difficult.
Indicator lights or indicators have been added to the front panels of some test instruments to augment graphical displays as the user interface. Indicators provide for the visual indication of basic information about selected parameters. A selected parameter may include the status of a link pulse in the case of a LAN. Basic information about selected parameters may include the presence or absence of a link pulse on a LAN being tested, the presence or absence of an error condition, or the detection of a collision. Indicators are often implemented using light emitting diodes (LEDs) which require relatively little power, are easy to see even in low ambient light, and allow for fast cognition of the basic information by the user of the test instrument.
Indicators in prior art instruments are typically located on the front panel adjacent to a permanent label and with no visual linkage to softkeys, thus limiting their ability to be used in multiple roles. Such indicators have not been visually associated with the operation of the graphical display and softkeys in prior art instrument designs. Without this visual association, an error indicator will show that further investigation is needed using detailed information but provides no visual prompt as to how to proceed in order to obtain the detailed information appropriate for that error indicator. Because the visual association between the indicator and user action is not readily apparent, the user is likely to be confused as to what action is required.
Therefore, it would be desirable to provide a graphical user interface for a test instrument employing a set of softkeys with a set of indicators that are directly linked to the softkeys to provide a visual prompt for further actions. It would be further desirable that the indicators display basic information about selected parameters in parallel fashion using a selected set of colors for fast visual interpretation by the user.